A grain of salt? DiDio is a professional liar. I don't believe anything he says, and neither should anyone else.
[DiDio] said: "It was selling okay, but we had greater expectations for that line. There's a lot of those characters that I feel we've told a lot of stories with, so at this particular moment we'll give the title a rest, and maybe give some of those characters a rest."
I can understand that the company is concerned that their terrible decision to alienate existing fans hasn't resulted in a long-term sales gains for the rebooted titles. But let's not place the blame on the rebooted characters. It's not their fault they are full of angst and look stupid.
If we look at his statement at face value in that interview about characters needing to be rested, only two members of the JLI as of issue #1 were being used elsewhere: Batman and Guy Gardner. Clearly, DC doesn't want to rest Batman, as he's their best selling character and simply teasing his cameo appearance in a book boosts its sales. Green Lantern is DC's second best-selling brand, so it's not hurting to have one of the half-dozen familiar Lanterns in the book.
In the series' second story arc, the team has added (or according to solicitations plans to add) Batwing and Firehawk, both of whom are also already in other books. OMAC was added after his book was canceled. However, none of these three characters has any significant history or continuity to speak of. None of these characters had appeared in scarcely more than 3 issues before the JLI cancellation. Fire, Ice, Vixen, August General, Rocket Red? Godiva? Some of these characters haven't even had lines in the issues published so far. (Vixen fans, in particular, should be furious at how she's been under-utilized.) Hard to justify these characters "need rest" when they are barely used. If this cancellation was due to overuse of any of these characters, it must be happening on an alternate Earth.
DiDio's job is to make news and sell comics, not to tell us anything truthful or even useful. Taking salt while listening to DiDio is just going to raise our blood pressure. Best just to ignore the man entirely.